Zipper tape and zipper-tape-equipped bag

ABSTRACT

A zipper tape includes a male member and a female member that bite each other. The male member has a head, a projection at the tip of the head, and a recess located at a connecting portion between the projection and the tip of the head. The female member has first and second claw members facing each other, a valley between the first and second claw members, and a pair of protrusions located at the top of the valley. When the male member and the female member bite each other, at least a part of the inner surface of the first claw member of the female member and at least a part of the inner surface of the second claw member of the female member come into surface contact with at least a part of the surface of the head of the male member. The valley of the female member receives the projection of the male member, and the protrusions of the female member fit into the recesses of the male member.

TECHNICAL FIELD

The present invention relates to a zipper tape and a zipper-tape-equipped bag.

BACKGROUND ART

A bag that can be freely opened and closed by providing, at its opening portion, a belt-shaped biting tool (zipper tape) comprising a male member and a female member is used principally in the food industry. Such a bag is also used as a bag for bedding or clothing.

Patent document 1 has disclosed a zipper having a male member 10 and a female member 20 that bite each other, wherein pinch valves 25 and 26 are provided between claw members 22 and 24 of the female member 20, as shown in FIG. 6. When biting, the pinch valves 25 and 26 pinch and lift a head 12 of the male member 10 so that the male member 10 and the female member 20 are kept in close contact.

However, the sealing performance of this zipper is inadequate because the male and female members are not in surface contact.

Patent document 2 has disclosed a zipper comprising a male member 30 and a female member 40 as shown in FIG. 7. In this zipper, a head 32 of the male member 30 comes into surface contact with a part of the inner side surface of a claw member 42 of the female member 40 and a part of the inner side surface of a claw member 44 of the female member 40, and the claw members 42 and 44 clamp and seal in the head 32.

This zipper is improved in sealing performance because the male and female members are in surface contact, but this zipper has the following various problems.

As the head of the male member is clamped by the tips of the claw members located apart from the base portion of the female member, clamping force is weak. If a load is applied to the tips of the claw members of the female member, the distance between the claw members increases, and the sealing performance may be impaired. When the claw members of the female member are so long as to touch the shaft of the male member, the claw members of the female member tend to be expanded at the boundary (the expanded claw members of the female member) of a fitted portion and an unfitted portion if the zipper is kept open for a long time, so that the sealing performance may decrease. The head of the male member is arc-shaped, which makes it difficult to align and fit the male and female members. If the zipper deforms at a side seal during the production of a bag, the sealing performance may be impaired, so that an advanced bag production technique is required during the bag production.

-   [Patent document 1] Japanese Patent Publication Laid-open No.     63-96040 -   [Patent document 2] Japanese Patent Publication Laid-open No.     7-309351

DISCLOSURE OF THE INVENTION

A zipper tape having high sealing performance is provided.

According to the present invention, a zipper tape and a zipper-tape-equipped bag below are provided.

1. A zipper tape includes a male member and a female member that bite each other,

the male member having a head, a projection at the tip of the head, and a recess located at a connecting portion between the projection and the tip of the head,

the female member having first and second claw members facing each other, a valley between the first and second claw members, and a pair of protrusions located at the top of the valley,

wherein when the male member and the female member bite each other, at least a part of the inner surface of the first claw member of the female member and at least a part of the inner surface of the second claw member of the female member come into surface contact with at least a part of the surface of the head of the male member, and

the valley of the female member receives the projection of the male member, and the protrusions of the female member fit into the recess of the male member.

2. The zipper tape according to 1, wherein the width of the projection of the male member is greater than the distance between the pair of protrusions of the female member, and smaller than the distance between the tiptops of the first and second claw members of the female member.

3. The zipper tape according to 1 or 2, wherein the female member has clasps projecting from the tips of the first and second claw members so as to face each other, and the length of the clasp is equal to or less than half the length of a clasp reception formed by the rear surface of the head.

4. A bag equipped with the zipper tape according to any one of 1 to 3.

According to the present invention, a zipper tape having high sealing performance can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a zipper tape comprising a male member and a female member according to one embodiment of the present invention;

FIG. 2 is a diagram showing how the male member and the female member of FIG. 1 bite each other;

FIG. 3 is a diagram showing the dimensions of parts of the male member of FIG. 1;

FIG. 4 is a diagram showing the dimensions of parts of the female member of FIG. 1;

FIG. 5 is a photograph of a zipper tape manufactured in Example 1;

FIG. 6 is a diagram showing a conventional zipper tape comprising a male member and a female member;

FIG. 7 is a diagram showing another conventional zipper tape comprising a male member and a female member;

FIG. 8 is a diagram showing the dimensions of parts of a male member used in Comparative example 1;

FIG. 9 is a diagram showing the dimensions of parts of a female member used in Comparative example 1;

FIG. 10 is a diagram showing the dimensions of parts of a male member used in Comparative example 2; and

FIG. 11 is a diagram showing the dimensions of parts of a female member used in Comparative example 2.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment(s) of the present invention will be described with reference to the drawings. However, the embodiment(s) is illustrative only, and the present invention is not limited to the embodiment(s).

A zipper tape according to one embodiment of the present invention is shown in FIG. 1. This zipper tape comprises a male member 100 and a female member 200 that bite each other.

The male member 100 includes a base 110, a head 120, and a rod-like coupling portion 130 that couples the head 120 to the base 110. The head 120 is substantially semispherical, and has a tip 122 and a rear surface 124. The substantially semispherical shape not only includes a semispherical shape but also includes, for example, a heart shape and an arrowhead shape.

The rear surface 124 of the head 120 is greater than the section of the coupling portion 130, and the coupling portion couples to substantially the center of the rear surface of the head. A part of the rear surface 124 of the head that is not coupled to the coupling portion 130 forms clasp receptions 124.

The tip 122 of the male member 100 has a projection 126. A recess 128 is present in a connecting portion between the tip 122 and the projection 126, that is, at the base of the projection 126.

The female member 200 includes a base 210, arc-shaped first and second claw members 220 and 230 facing each other, and clasps 222 and 232 projecting from the tips of the first and second claw members 220 and 230 so as to face each other. The clasps 222 and 232 are smaller in length than the clasp receptions 124 of the male member. A valley 240 for receiving the projection 126 at the tip of the male member is present between the first and second claw members 220 and 230. A pair of protrusions 242 are present at the top of the valley 240, that is, at the bases of the claw members 220 and 230.

As shown in FIG. 2, if the male member 100 is inserted into the female member 200, the projection 126 at the tip of the female member comes into the valley 240 between the first and second claw members, and the pair of protrusions 242 of the female member fit into the recesses 128 of the male member. Further, at least a part of the inner surface of the first claw member 220 of the female member and at least a part of the inner surface of the second claw member 230 of the female member, that face each other, come into surface contact with at least a part of the surface of the head 120 of the male member. In this condition, sealing performance is enhanced.

Furthermore, clamping force for clamping the projection 126 at the head of the male member is strong in the valley 240 in the female member.

Moreover, in the male member 30 shown in FIG. 7, the tip of the head 32 is in a flat arc shape, and may therefore come out of position and out of track. In contrast, according to the present embodiment, the projection 126 is formed at the tip 122, and the clasps 222 and 233 guide this projection 126, so that the male member 100 and the female member 200 can be easily aligned.

When the male member 100 and the female member 200 bite each other, the clasps 222 and 232 of the female member come into contact, preferably, surface contact with the rear surface 124 of the male member. This further enhances sealing performance.

In the present embodiment, the width a of the projection of the male member is preferably greater than the distance A of the protrusions of the female member (see FIGS. 3 and 4). If the width a is greater than the distance A, the female member lifts the male member, and contact pressure between the protrusions 242 and the recesses 128 and contact pressure between the clasps 222 and 232 and the clasp receptions 124 increase.

The width a of the projection of the male member is preferably smaller than a distance E between the tiptops of the claw members of the female member (see FIGS. 3 and 4). If the width a is smaller than the distance E, the male and female members are easily aligned when fitted together, and is easily fitted together.

The length c from the rear end of the male member to the front end of the male member is preferably greater than the length C from the top of the valley of the female member to the base of the clasp (see FIGS. 3 and 4). If the length c is greater than the length C, the head lifts the clasps of the claw members, and contact pressure between the clasps and the clasp receptions increases.

Here, c is not easily recognized in the case of a curve shown in FIG. 5, inflection points of R of the projection and R of the recess are defined as ends.

The length D from the clasp of the female member is preferably equal to or less than half the length d of the clasp reception of the male member (see FIGS. 3 and 4). If the clasp is shorter than the clasp reception, the claw members of the female member do not tend to be expanded and the sealing performance does not deteriorate even if the zipper is kept open for a long time.

In the configuration described above, dotted circular marks in FIG. 2 indicate surface contact, and solid circular marks indicate contact pressure.

Here, if the width b of the head of the male member is greater than the distance B of the inner surfaces of the claw members of the female member (see FIGS. 3 and 4), the contact pressure of surface contact between the claw members of the female member and the head of the male member preferably increases.

The zipper tape according to the present invention may include the arrangement of pairs of male and female zippers.

The material of the zipper tape may be selected from materials that have heretofore been used for zipper tapes, for example, low-density polyethylene, straight-chain low-density polyethylene, ethylene-vinyl acetate copolymer, and polypropylene. For a high-sealing zipper, a soft resin such as polyethylene or ethylene copolymer is particularly preferable.

The configuration described above allows the zipper tape according to the present embodiment to maintain sealing performance in various conditions in which the zipper tape is used. As long as the protrusions 242 are in contact with the projection 126 or the recesses 128, this zipper tape maintains sealing performance, and is therefore easily squashed.

A bag according to the present invention is equipped with the zipper tape described above.

EXAMPLES Example 1

A zipper tape provided with two biting portions shown in FIGS. 1 to 4 was manufactured from low-density polyethylene (density 926 kg/m³).

The dimensions of parts of the biting portions were as follows: a=0.63 mm, A=0.55 mm, b=1.24 mm, B=1.07 mm, c=0.45 mm, C=0.44 mm, d=0.36 mm, D=0.17 mm, and E=1.07 mm.

A bag was manufactured by a general three-way bag making machine using a two-layer laminated film that includes a 15 μm biaxial stretched nylon film (G-100 manufactured by Idemitsu Unitech Corporation) and a 50 μm straight-chain low-density polyethylene film (LS-711C manufactured by Idemitsu Unitech Corporation) and also using the zipper tape described above. Thus, a zipper-tape-equipped bag was manufactured.

Comparative Example 1

A zipper-tape-equipped bag was manufactured in similar fashion to Example 1 except that biting portions shown in FIGS. 8 and 9 were manufactured as biting portions.

The dimensions of parts of the biting portions were as follows: b=1.24 mm, B=1.07 mm, c=0.77 mm, C=0.78 mm, d=0.36 mm, D=0.30 mm, and E=1.07 mm.

Comparative Example 2

A zipper-tape-equipped bag was manufactured in similar fashion to Example 1 except that biting portions shown in FIGS. 10 and 11 were manufactured as biting portions.

The dimensions of parts of the biting portions were as follows: A=0.34 mm, b=0.72 mm, B=0.87 mm, c=0.58 mm, C=0.57 mm, d=0.22 mm, D=0.33 mm, and E=1.07 mm.

Evaluation Example 1

The zipper-tape-equipped bags manufactured in Example 1, and Comparative examples 1 and 2 were evaluated as below. The results are shown in Table 1.

[Evaluation Method]

(1) Sealing Performance after Opening/Closing

After the zippers were opened and closed ten times in succession, a pinhole checker (manufactured by Mitsubishi Gas Chemical Corporation) was enclosed in the bags to find out whether there is any leakage from the zippers.

(2) Sealing Performance after the Zippers were Kept Open

After the zippers were kept open up to half the width of the bags for 24 hours, the zippers were again fitted, and the pinhole checker was enclosed in the bags to find out whether there is any leakage from the zippers.

[Evaluation Criteria]

◯: No leakage after 24 hours

Δ: Leakage found after 24 hours

x: Leakage found after one hour

TABLE 1 Evaluation results After opening/ After zippers Comprehensive closing were kept open evaluation Example 1 ∘ ∘ ∘ Comparative ∘ x x example 1 Comparative Δ x x example 2

INDUSTRIAL APPLICABILITY

A zipper tape and a zipper-tape-equipped bag according to the present invention are used for a bag to pack, for example, food, clothing or bedding in a sealed condition.

While several embodiments and/or examples of the present invention have been described above in detail, it will readily occur to a person skilled in the art that modifications may be made to the exemplary embodiments and/or examples substantially without departing from the novel teachings and advantages of the present invention. Accordingly, such modifications fall within the scope of the present invention.

The entire disclosures of the documents described in this specification are incorporated herein by reference. 

1. A zipper tape comprising a male member and a female member that bite each other, the male member having a head, a projection at the tip of the head, and recesses located at a connecting portion between the projection and the tip of the head, the female member having first and second claw members facing each other, a valley between the first and second claw members, and a pair of protrusions located at the top of the valley, wherein when the male member and the female member bite each other, at least a part of the inner surface of the first claw member of the female member and at least a part of the inner surface of the second claw member of the female member come into surface contact with at least a part of the surface of the head of the male member, and the valley of the female member receives the projection of the male member, and the protrusions of the female member fit into the recesses of the male member.
 2. The zipper tape according to claim 1, wherein the width of the projection of the male member is greater than the distance between the pair of protrusions of the female member, and smaller than the distance between the tiptops of the first and second claw members of the female member.
 3. The zipper tape according to claim 1, wherein the female member has clasps projecting from the tips of the first and second claw members so as to face each other, and the length of the clasp is equal to or less than half the length of a clasp reception formed by the rear surface of the head.
 4. A bag equipped with the zipper tape according to claim
 1. 